Xinsheng IntelligentWritings50 questions about industrial cameras (3)

21: How is a line scan camera defined?

A line scan industrial camera, as the name suggests, is in the shape of a "line". Although it is also a two-dimensional image, it is extremely long, with a length of several K, and a width of only a few pixels. This camera is generally only used in two situations:

1. The measured field of view is a slender strip, which is mostly used for detection problems on the drum.

2. Requires a great field of view or extreme precision.

22: What are the general steps for choosing an industrial camera?

The first step is to know the system accuracy requirements and industrial camera resolution;

The second step is to know the system speed requirements and the imaging speed of the industrial camera;

The third step is to consider the industrial camera and the frame grabber together, because it involves the matching of the two;

The fourth step is price comparison.

23: How to use the precision required by the machine vision system to calculate the resolution (pixels) of the camera that needs to be selected?

Knowing the actual detection accuracy to infer how many pixels of the industrial camera should be used can be calculated by the formula: X-direction system accuracy (X-direction pixel value) = field of view (X-direction) / CCD chip pixel number (X-direction); Y Orientation system accuracy (Y direction pixel value) = field of view (Y direction) / CCD chip pixel number (Y direction) to obtain. Of course, the theoretical pixel value should be comprehensively considered by the system accuracy and sub-pixel method;

24: How to deduce what speed industrial camera should be selected according to the actual required detection speed?

The single operation speed of the system = system imaging (including transmission) speed + system detection speed, although the system imaging (including transmission) speed can be theoretically calculated according to the asynchronous trigger function of industrial cameras, shutter speed, etc., the best method is to use software for actual test;

25: Which industrial cameras need to be matched with frame grabbers for normal use?

The industrial camera needs to be well matched with the frame grabber to be used normally. Generally, it needs to match the following:

a. Video signal matching, there are two formats for black and white analog signal cameras, CCIR and RS170 (EIA), usually capture cards support both industrial cameras at the same time;

b. Resolution matching, each board only supports cameras within a certain resolution range;

c. Matching of special functions. If you want to use the special functions of the camera, first determine whether the board card used supports this function. For example, if you want to take pictures with multiple cameras at the same time, the capture card must support multiple channels. If the camera scans line by line , then the capture card must support progressive scan;

d. Interface matching, to determine whether the interface of the camera and the board match. Such as CameraLink, Firewire1394 and so on.

26: What is the difference between an industrial camera with a USB interface and an industrial camera with a 1394 interface?

The main factors that affect our choice of USB camera and 1394 camera from the interface are as follows:

a) Protocol specification: There are more than 50 industrial specification protocols related to 1394 equipment, involving cameras, industrial cameras, and other equipment. Most of the 1394 industrial cameras from various manufacturers follow the DCAM industrial specification. The USB industrial camera interface is a recent commercial specification developed from commercial PC applications.

b) Power supply mode: The operating voltage of 1394 industrial camera is 8 to 30VDC, and the operating voltage of USB industrial camera is 5VDC. From the perspective of power supply range, the 1394 interface meets the DC power supply requirements of individual equipment in the industrial field, such as 12VDC or 24VDC; while the USB interface uses electronic circuit TTL standard voltage power supply, which is generally used for internal power supply of equipment.

c) Operating system coordination: The 1394 interface industrial camera can keep the original address unchanged after the system is restarted, while the USB interface industrial camera needs to be re-assigned by the system after each startup.

d) Data transmission: The 1394 interface has inherent advantages when dealing with data transmission of multiple industrial cameras. From the development background, the USB interface is a new generation of high-speed data transmission interface to undertake the RS232 interface, and the industrial camera of the 1394 interface is designed as a substitute for SCSI and PCI bus.

27: What is the difference between smart industrial cameras and general industrial cameras?

The difference between a smart camera and an industrial camera, in short: a smart camera is a highly integrated miniature machine vision system; an industrial camera is one of the components of a machine vision system.

28: What is the main function of the image acquisition unit in the smart industrial camera?

In a smart camera, the image acquisition unit is equivalent to a common CCD/CMOS camera and an image acquisition card. It converts the optical image to analog/digital image and outputs it to the image processing unit.

29: What is the role of the image processing unit in the intelligent industrial camera

In a smart industrial camera, the image processing unit is similar to an image acquisition and processing card. It can store the image data of the image acquisition unit in real time, and perform image processing under the support of image processing software.

30: What is the main role of image processing software in smart industrial cameras?

The image processing software mainly completes the image processing function under the support of the hardware environment of the image processing unit. Such as geometric edge extraction, Blob, grayscale histogram, OCV/OVR, simple location and search, etc. In smart cameras, the above algorithms are packaged into fixed modules, which can be directly applied by users without programming.